Figure 5

Eigenvector clusters indicate aggregation levels. Elements of the fourth, seventh and eighth eigenvector of the codon substitution matrix. Codons that map to the same amino acids are clustered, which indicate the standard genetic code. There are also clusters of amino acids in turn (marked with the same colors as in Figure 3 and 4): {A, T}, {I, M, V}, {E, D} and {K, R}, which indicate that these form higher order aggregates.